Reports

Air Temperature

Relative Humidity

Atmospheric Pressure

Wind

Precipitation

Rainfall Events

December 2021 Compared to the Climate Means

The Two Faces of December 2021

The first half of December 2021 was characterized by frequent rainy episodes. Almost all of last month’s 62.1 mm of rain were measured on ten days of rain in the first half of the month. The meteorological situation changed almost like a switch midway through. The second half of December 2021 was characterized by largely dry weather conditions. This abrupt change in the meteorological situation may be attributed to the expansion of a blocking anticyclone across the western Mediterranean. This continued to expand and strengthen across mainland Europe too at the end of the month. This ensured fine weather for the Maltese Islands, as the incoming storm systems were deviated to the north. In a stark contrast to October 2021 and November 2021, last month registered just over a half of the climatic average in terms of rain.

Overall, where temperature is concerned, December 2021 turned out to be markedly colder than the climate norm. In fact, last months mean temperature of 13.4°C was a solid 1.1°C colder than that of a typical December. An episode of wintry temperatures halfway through the month contributed to this. Minimum temperatures dipped to below 10°C on a total of 13 nights. Last month’s coldest minimum of 6.4°C was  in the early hours of Thursday 16^th. The coldest day overall was Sunday 19^th with maximum and minimum temperatures of 12.6°C and 7.4°C respectively. Conversely, the days around Christmas and New Year’s were characterized by very warm temperatures that were advected from the Sahara Desert across to parts of the Mediterranean and western Europe.

Wind behavior also reflected the switch in atmospheric pressure patterns halfway through the month. The first half of December 2021 was notably windy, with no less than three gales being registered. The second half of last month was much calmer, as a blocking anticyclone ensured stability across the region.

Rainfall Totals around the Maltese Islands in December 2021 (and since last September 1st):

Għarb: 62.1 mm (490.2 mm)

Marsalforn: 49.5 mm (545.9 mm)

Victoria: 60.4 mm (503.5 mm)

Xewkija: 32.0 (468.4 mm)

Nadur: 49.8 mm (532.4 mm)

Mellieħa: 45.4 mm (476.4 mm)

Buġibba: 36.2 mm (507.9 mm)

Naxxar: 35.4 mm (492.5 mm)

Dingli: 32.1 mm (393.9 mm)

Mġarr: 34.3 mm (478.2 mm)

Mosta: 45.3 mm (399.9 mm)

Msida: 52.2 mm (478.6 mm)

Sliema: 50.1 mm (464.4 mm)

Valletta: 28.8 mm (306.2 mm)

Imqabba: 26.6 mm (446.9 mm)

Żabbar: 44.0 mm (511.6 mm)

Birżebbuġa: 26.2 mm (356.1 mm)

NATIONAL MEAN: 41.8 mm (461.9 mm)

Air Temperature

Relative Humidity

Atmospheric Pressure

Wind

Precipitation

Rainfall Events

November 2021 Compared to the Climate Means

Wetter than Average Autumn continues in November 2021

The wetter than average trend set earlier in autumn was maintained throughout the month of November 2021. A total of 177.5 mm of rain was measured by our weather station. This is almost double the climate norm of 93.6 mm. This year’s autumn is the wettest in years, and has helped relieve the drought that had gripped the Maltese Islands in previous years. This didn’t come without any consequences, unfortunately. The bulk of the rain came from rainfall events that dotted the second half of the month. There were 11 days of rain last month. 2 of these were severe rainfall events. The thunderstorms of 11^th and 25^th November both struck in the early hours. They each dumped in excess of 100 mm of rain over several localities, sparking flash floods. The one on the 25^th was particularly dangerous, with a number of people having to be rescued from the flooding. Total rainfall since last September 1^st now stands at 428.1 mm. That is more than what was measured throughout the 2020/2021 rainfall season.

With regards to temperature, November 2021 turned out to be marginally warmer, especially where daytime maximum temperatures are concerned. This is mainly due to a spell of balmy temperatures that lasted much of the first half of the month. Winds from the south fanned warm air from the Sahara Desert across the central Mediterranean, elevating temperatures to well above average. The return of the westerlies brought colder temperatures towards the end of the month. Last month’s mean temperature of 18.0°C was 0.4°C warmer than what one would expect in a typical November.

Rainfall Totals around the Maltese Islands in November 2021 (and since last September 1st):

Għarb – 177.5 mm (428.1 mm)

Marsalforn – 221.9 mm (496.4 mm)

Victoria – 171.2 mm (443.1 mm)

Xewkija – 216.0 mm (436.4 mm)

Nadur – 233.5 mm (482.5 mm)

Mellieħa – 236.8 mm (431.0 mm)

Buġibba – 230.2 (471.7 mm)

Naxxar – 225.8 mm (457.1 mm)

Dingli – 130.1 mm (361.8 mm)

Mġarr – 191.7 mm (443.9 mm)

Mosta – 164.1 mm (354.6 mm)

Msida – 176.2 mm (426.4 mm)

Sliema – 175.4 mm (414.3 mm)

Valletta – 115.8mm (277.4 mm)

Imqabba – 144.2 mm (420.3 mm)

Żabbar – 174.9 mm (467.4 mm)

Birżebbuġa – 105.6 mm (329.9 mm)

NATIONAL MEAN – 181.1 mm (420.3 mm)

Air Temperature

Relative Humidity

Atmospheric Pressure

Wind

Precipitation

Rainfall Events

September 2021 Compared to the Climate Means

Warmer and Drier in September 2021

Overall, October 2021 turned out to be significantly warmer than the climate norm. At 25.9°C, temperatures were 1.3°C warmer than the mean. Temperatures were above average on 19 days. This may be attributed to the central Mediterranean being covered by a persistent north African high pressure system. This fanned hot air from the Sahara Desert towards our region, maintaining air temperatures at an elevated level. The hottest day last month was on the 18^th, when the mercury spiked to 31.9°C.

September 2021 was also drier than average. The 9.6 mm of rain measured last month all fell in the first week. This accounted for far less than a quarter of the climate mean. This was the result of anticyclonic conditions that prevailed over the central Mediterranean for a large part of the month. These acted as a barrier, which prevented low pressure systems from reaching the central Mediterranean.

The more stable meteorological conditions also meant weaker winds.

Rainfall Totals around the Maltese Islands in September 2021 (and since last September 1st):

Għarb – 9.6 mm (9.6 mm)

Marsalforn – 15.2 mm (15.2 mm)

Victoria – 18.4 mm (18.4 mm)

Xewkija – 14.8 mm (14.8 mm)

Nadur – 12.9 mm (12.9 mm)

Mellieħa – 16.8 mm (16.8 mm)

Buġibba – 34.3 (34.3 mm)

Naxxar – 34.3 mm (34.3 mm)

Dingli – 46.2 mm (46.2 mm)

Mġarr – 25.9 mm (25.9 mm)

Mosta – 25.0 mm (25.0 mm)

Msida – 22.8 mm (22.8 mm)

Sliema – 25.4 mm (25.4 mm)

Valletta – 21.1mm (21.1 mm)

Imqabba – 13.3 mm (13.3 mm)

Żabbar – 12.5 mm (12.5 mm)

Birżebbuġa – 12.1 mm (12.1 mm)

NATIONAL MEAN – 21.2 mm (21.2 mm)

Air Temperature

Relative Humidity

Atmospheric Pressure

Wind

Precipitation

Rainfall Events

October 2021 Compared to the Climate Means

October 2021 One of the Wettest Ever

October 2021 turned out to be noticeably cooler than average. With a mean temperature of 20.6°C, last month was a solid 0.8°C cooler than the climate norm. Last month started off on a relatively warm note. This was short-lived, however. Successive pockets of cooler air from over Europe, coupled with the cooling effect of rain on a staggering 20 days, ensured a pattern of consistently cooler than average temperatures. A 13.9°C low, the coldest for October 2021, was registered on the 21^st. This was measured at around dawn, after a night of cooling under anticyclonic conditions. The very warm days at the start of the month were brought about by southerly winds which fanned hot air from north Africa towards the central Mediterranean. Last months warmest temperature of 27.6°C was measured on two days, the 4^th and 5^th.

The 241.0 mm of rain measured last month was almost three times more than the 83.3 mm expected in a typical October. This made October 2021 the third wettest October since record keeping began a century ago. Rain fell on 20 days last month, with rainfall events having been evenly distributed, bar for a brief dry spell in the third week of the month. Thunder was heard on 10 days. Hail was observed on 2 days. Total 24-hour rainfall exceeded 25 mm on 4 days. The wettest day was the 3^rd, when 69.5 mm of rain were recorded. Much of this rain fell in a few minutes in the very early hours, during an intense thunderstorm that packed rainfall rates of over 300 mm/hr, winds of up to Force 7 and dangerous cloud-to-ground lightning. Xlendi, notable for frequent in storms, bore the brunt of it all. The valley system that empties in Xlendi collects run-off from the localities which received the most rainfall from these thunderstorms. Cars were carried to the sea and debris littered the streets. Rainfall during the thunderstorm was most intense between 3:28 a.m. and 3:39 a.m. when a staggering 37.8 mm of rain were dumped in just 11 minutes.

October 2021 turned out to be noticeably cooler than average. With a mean temperature of 20.6°C, last month was a solid 0.8°C cooler than the climate norm. Last month started off on a relatively warm note. This was short-lived, however. Successive pockets of cooler air from over Europe, coupled with the cooling effect of rain on a staggering 20 days, ensured a pattern of consistently cooler than average temperatures. A 13.9°C low, the coldest for October 2021, was registered on the 21^st. This was measured at around dawn, after a night of cooling under anticyclonic conditions. The very warm days at the start of the month were brought about by southerly winds which fanned hot air from north Africa towards the central Mediterranean. Last months warmest temperature of 27.6°C was measured on two days, the 4^th and 5^th.

The 241.0 mm of rain measured last month was almost three times more than the 83.3 mm expected in a typical October. This made October 2021 the third wettest October since record keeping began a century ago. Rain fell on 20 days last month, with rainfall events having been evenly distributed, bar for a brief dry spell in the third week of the month. Thunder was heard on 10 days. Hail was observed on 2 days. Total 24-hour rainfall exceeded 25 mm on 4 days. The wettest day was the 3^rd, when 69.5 mm of rain were recorded. Much of this rain fell in a few minutes in the very early hours, during an intense thunderstorm that packed rainfall rates of over 300 mm/hr, winds of up to Force 7 and dangerous cloud-to-ground lightning. Xlendi, notable for frequent in storms, bore the brunt of it all. The valley system that empties in Xlendi collects run-off from the localities which received the most rainfall from these thunderstorms. Cars were carried to the sea and debris littered the streets. Rainfall during the thunderstorm was most intense between 3:28 a.m. and 3:39 a.m. when a staggering 37.8 mm of rain were dumped in just 11 minutes.

Rainfall Totals around the Maltese Islands in October 2021 (and since last September 1st):

Għarb – 241.0 mm (250.6 mm)

Marsalforn – 259.3 mm (274.5 mm)

Victoria – 253.5 mm (271.9 mm)

Xewkija – 205.6 mm (220.4 mm)

Nadur – 236.1 mm (249.0 mm)

Mellieħa – 177.4 mm (194.2 mm)

Buġibba – 207.2 mm (241.5 mm)

Naxxar – 197.0 mm (231.3 mm)

Dingli – 185.5 mm (231.7 mm)

Mġarr – 226.3 mm (252.2 mm)

Mosta – 165.5 mm (190.5 mm)

Msida – 227.4 mm (250.2 mm)

Sliema – 213.5 mm (238.9 mm)

Valletta – 140.5 mm (161.6 mm)

Imqabba – 262.8 mm (276.1 mm)

Żabbar – 292.5 mm (305.1 mm)

Birżebbuġa – 212.2 mm (224.3 mm)

NATIONAL MEAN – 218.0 mm (239.2 mm)

Air Temperature

Relative Humidity

Atmospheric Pressure

Wind

Precipitation

August 2021 Compared to the Climate Means

Significantly Hotter than Average in August 2021

August 2021 was the hottest month of the year. The mean temperature exceeded the norm by a staggering 1.6°C. Maximum temperatures were 1°C hotter than average. Nighttime lows were 2.2°C warmer than average. This wider anomaly may be attributed to the warmer than average sea surrounding the Maltese Islands. A very warm sea inhibits nighttime cooling. The hottest day was the 1^st, with a maximum temperature of 37.3°C. Temperatures exceeded the 40°C mark on the day, in more central spots on Malta. A total of eighteen days registered a maximum temperature greater than the climate mean. The coolest temperature of 21.1°C was measured at dawn on the 20^th. This was one of only a handful of nights with a minimum temperature dipping to below average.

A heavy rain shower was observed over a handful of localities in central Malta on 22^nd August. Most places remained dry on the day, however. This extended the dry run for the driest of localities to 150 days.